Wiping or doctoring devices for removing excess coating from sheet material



(Mi. m!

v SMITH 2,774,329

Dec. 18, 1956 R.

WIPING OR DOCTORING DEVICES FOR REMOVING EXCESS COATING FROM SHEET MATERIAL 3 Sheets-Sheet 1 Filed Jan. 25. 1954 WIPING DR 'ooc'romuq" Dec. 18, 1956 R. v. SMITH WIPING OR DOCTORING DEVICES FOR REMOVING EXCESS COATING FROM SHEET MATERIAL 3 Sheets-Sheet 2 Filed Jan. 25. 1954 INVENT w w R o T C W w w R BQL? Was-W A 77 EN N Dec. 18, 1956 v. SMITH 2,774,329

WIPING OR DOCTORING DEVICES FOR REMOVING EXCESS COATING FROM SHEET MATERIAL Filed Jan. 25. 1954 3 Sheets-Sheet 3 United StatesPatefitO WIPING R DOCTORING DEVICES FOR RE- MOVING EXCESS COATING FROM SHEET MATERIAL Roland V. Smith, Ottawa, Ontario, Canada, assignor to E. B. Eddy Company, Hull, Quebec, Canada, a body corporate Application January 25, 1954, Serial No. 405,909

11 Claims. (Cl. 118118) The present invention relates to a wiping or doctoring device and more particularly to a Wiping or doctoring device having a rotating wiping or doctoring edge which removes excess coating from sheet material.

-It is an object of the present invention to obtain a rotating edge on a wiping device which will wipe evenly and uniformly along its length throughout its life.

Another object of the invention is to obtain a rotating edge on a wiping device which will not be subject to rapid wear.

I It is a further object of the invention to obtain a rotating edge on a wiping device which will be easily and rapidly replaceable with a minimum stoppage time and at minimum cost.

Another object of the invention is to obtain a wiping device with a rotating edge which will maintain a high degree of cleanliness free from hardening of the coating liquid.

Still another object of the invention is to obtain on a wiping device a rotating edge rod which will be held to the body of the wiping device under an even and secure pressure throughout its length.

Further objects of the invention will be set out below.

Wiping devices with rotating wiping edges at present used in the manufacture of coated sheet material are of two main types. In the first type, the rotating wiping rod rests on the blade body and is secured at each of its ends. In the alternate type the wiping rod is mounted on the body of the wiping device and is held along its entire length by a pair of elongated clamps within which the rod rotates. It has been found that in the first type of wiping device the wiping rod bends out of true alignment after a short period of working time and for this reason the alternate type of device has been employed. However, in the latter case it has been found that friction between the clamps and the rotating wiping rod causes the rod to wear excessively. Also in order to obtain a suflicient exposed surface on the wiping rod for the sheet to make inti mate contact the clamping jaws must be separated to a width which is close to the diameter of the rod, and the rod then tends to spring from the grip of the clamps. When wearing excessively, unevenness of the cooperating surfaces of the wiping rod and clamps becomes suflicient to allow some of the excess coating material to pass the scraping edge of the clamps and dry on the rod within the clamps which subsequently causes the coated sheet material to appear streaked. Excessive wear also results in unevenness of clamping pressure. Finally, the devices at present in use require frequent replacement at relatively high cost.

The present invention overcomes these difiiculties by securing the rotating wiping rod to the body of the wiping device by magnetic attraction. Magnets are placed on the body of the device and the wiping rod is held between the magnet poles in a suitable groove or seat. The magnets, if they are a series of individual units, are so spaced that a uniform force of attraction is exerted on the rod.

2,174,329 Patented Dec. 18, 1956 In addition, wiping material is placed between the rod and the groove in the-body of the device to clean the rod as it rotates.

This invention consists in the construction, combination and arrangement of parts hereinafter described and more particularly pointed out in the appended claims.

One convenient embodiment of the invention will now be described by way of example with respect to the accompanying drawings in which:

Figure l is aschematic diagram of the coating operation employing the wiping or doctoring device;

Figure 2 is a cross-sectional end view of the device;

Figure 3 is a side elevation;

Figure 4 is a bottom plan view;

Figure 5 is a cross-sectional end view of the device, including the mounting;

Figure 6 is a side elevation of the mounting;

Figure 7 is a cross-sectional view of a preferred rod seating, and

Figure 8 is a cross-sectional end view illustrating the electro-magnetic modification of the device.

The device consists of a series of U-shaped magnets 1 to which are attached continuous pole-pieces 2 and 3 extend ing the length of the series. The pair of pole-pieces 2 and 3 are wedge-shaped in cross-section and are attached together to form a single unit, separated preferably by a filler 4 of non-magnetic material. Bolts 5 of non-magnetic material may be used to attach together the members 2, 3 and 4. Non-magnetic dowels 5a may also be used to attach together the members 2, 3 and 4. The filler 4 is itself of wedge-shaped cross-section so that the pole pieces 2 and 3 converge, the narrow edges 6 of the pole-pieces 2 and 3 and being separated by only a small gap, whereas the wider edges 7 are separated by a wider gap equivalent in width to the gap between the inner edges of the arms 8 of the magnets 1. The edges 7 are bevelled in order that the pole-pieces 2 and 3 may sit flush with the arms 8 of the magnet. Bolts 9 of magnetic material passing through the magnets 1 secure the magnets to the pole-pieces. Thus a U-shaped magnet with extended converging arms is obtained.

The unit embodying the pole-pieces 2 and 3 and the filler 4 may itself be constructed in two sections 10 and 16a which are separable from each other, being held together by magnetic attraction along the contacting surfaces 11. The upper section 10a (shown in detail in Fig. 7) is merely a further continuation of the magnet arms 8 and the two parts 12 and 13 constituting the upper portion of the pole-pieces 2 and 3 are separated by a filler 14 of non-magnetic material. At the outer and converging edges 6 of the parts 12 and 13 (denoted earlier as the narrow edges 6 of the complete pole-pieces 2 and 3), a seat 15 is formed in the filler 14 and parts 12 and 13 for the containment of a rod 16 which is composed of magnetic material. The seat 15 is preferably shaped as a semi-cylindrical trough cut into the filler 14 and edges 6 along their entire length.

The parts 12 and 13 and the filler 14 must of course be secured together by further non-magnetic bolts 17. The bolts 5 and 17 and the dowels 5a are made of non-magnetic material in order that all the flux lines of the magnet 1 will pass across the gap between the edges 6 at the extremity of the pole-pieces 2 and 3. These flux lines pass across the seat 15 and hold the rod 16 therein. In this position the rod 16 can rotate on its longitudinal axis bu cannot move from the seat 15.

To ensure that the rod 16 is kept clean as it rotates, a layer of felt 17a is interposed between the seat 15 and rod 16. The felt 17a may be held in place on the seat 15 solely by the rod 16 or, in an alternative embodiment illustrated in Figure 7, -it may lap over the edges 6 of the parts 12 and 13 and be held in place by clamps 18 held held to the parts 12 and 13 by screws 19. Any other suitable wiping material may be used in place of felt for this operation. g V il' V The series of magnets 1 and the pole-pieces 2 and 3 are of suitable length in order that the rod 16 may cover thewidth of the sheet of coated material passing over it. To mount the device, two channels 20 are secured, facing back to back, on end plates 21 with a gap 2 2 between the 7 channels 26 sufficient to insert the series of magnets 1 attachedto the pole-pieces 2 and 3 as sho '11 in Figures and 6. Angles 23 are welded to the channels flush .with the upper edges of the flanges, and are spaced at intervals'sufficient to allow'the magnets 1 to be inserted between them into th e gap 22. The pole-pieces 2 and 3, with the magnets 1 bolted to them, are then placed. so that the edges 7 rest upon the angles 23 and the channels 29, and bolts 24 passing through the angles 23 are used to secure the pole-pieces 2 and 3 to them;

The end plates21 are bolted to a base 25 by bolts 26 inserted through arcuate slots 27 in the plates 21. A central bolt 28 anchored to the base 25 passes through the center point of each plate 21 and the plate 21 is able to pivot freely about the bolt 28. The angle of the wiping device to the coated sheet material passing over it can thus be varied through an angle limited by the length of the slots 27 and by tightening the bolts 26 the device may be secured at any desired positionwithin that limit.

Removal of the rotating wiping edge from the body of the device is effected by separating the sections 10 and 10a of the pole-pieces 2 and 3 from each other. If the magnets 1 are permanent magnets the two sections 10 and 10a may be separated by shearing along the surface 11.

. 32 and 33, is wound around said magnet 1 and an electric current can be passed through said coil 31 to createa magnetic field within the iron core.

A gripping projection 29 integral with thefiller 14 will allow a shearing force to be applied to the section 19a as shown in Figure 3. in an alternative embodiment a space 30 betweenthe fillers of the two sections it) and ltia may contain a collapsible tube 31 as shown in Figure 5.

When the two sections 10 and 1% are in contact, the tube 31 is deflated. To separate the two sectionsii! and 19a it is merely necessary to inflate the tube 31 and force the two sections apart by pneumatic or hydraulic pressure. If the magnets 1 are electro-magnets, it is merely necessary to cut off the current to separatethe sections it) and 19:; or to remove the rotating wiping edge.

a It will again be noted that the polepieces 2 and 3, the bolts 9, and the rod 16 are of magnetic material in order to produce a complete flux circuit in the device. Conversely, the bolts 5 and 17, the filler 4 (and 14), the bolts 24, the angles, 23, the channels 20 and the end plates 21 will be of non-magnetic material to prevent magnetic flux linesfrom straying out of the closed flux circuit; The rod 16 may be chrome plated for freer rotation, and the surfaces 11 may be chrome plated to assist 'in shearing the section 10 from the section 10a.

It is evident from the foregoing description thatthe applicant has made a useful invention. The machine is of simple construction and eflicient in operation and will be of great material advantage, to the industry in which it is employed. presented above is intended to'be in the nature of an example only and modifications to any degree may be made within the scope of the appended claims.

I claim: a

1. A wiping device for doctoring coated sheet material comprising a wiping rod of magnetic materiahrotatable about its longitudinal axis, a seat for said rod andmagnetic means holding said rod in said seat. 7

' 2. A device as claimed in claim 1 in which a material is interposed between said rod and said seat to continuously clean said rod.

3. A device as claimed in claim 2 in which said interposed material is felt.

4. A wiping device as claimed in claim 1 in which said.

seat comprises a non-inagnetic 'filler held between the free ends of the pole pieces of a .U-shaped magnet.

5. A Wiping device as claimed in claim 4 in which the pole pieces of said magnet are detachable from the main magnet is a permanent magnet.

body of said magnet- 6. A wiping device for doctoring coated sheet material comprising at least one U-shaped magnet having two converging pole pieces and a wiping rodof magnetic'material held 'by magnetic attraction in a seat which is formed betweenthe ends of said converging pole pieces of said magnet. t v

7. A wiping device as claimed in claim 6 in which said i terial, comprising a series of U-shaped magnets spaced with their pole-pieces inalignment, a non-magnetic filler interposed between said pole-pieces and having a shaped seat at its outer edge and along its longitudinal axis, and a rotatable rod of magneticv material held in said seat by the attraction of said magnets.

11. A device as claimed in claim 10 in which said polepieces and said filler comprise a unit detachable from the base of said magnets and held to said base by magnetic attraction. V I

References Cited in the file of this patent UNITED' STATES PATENTS Sherman et al. June 10, 1952 It should be understood that the description 

